Overview

The Substrate system in UE 5 revolutionizes Material authoring by replacing fixed shading models such as Default Lit and Clear Coat with a versatile, modular framework: Materials are represented as “Slabs of matter” using principled BSDF parameters with well-defined units. These Slabs form a graphical network where operations such as mixing and layering occur.

Overall, Substrate addresses the limitations of legacy UE shading models such as Default Lit and Clear Coat, allowing for smoother transitions and layering across meshes, overcoming issues such as whitish artifacts during Metallic parameter blending.

How it works

The system is fundamentally built upon components called Slabs, which have a direct connection to physical reality. A Substrate Slab is composed of two essential elements: the interface and the medium.

Figure Appendix.1: The Slab’s composition

• The interface represents the boundary where light interacts...